libavutil/timecode.c

   1 /*
   2  * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
   3  * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * Timecode helpers
  25  * @see https://en.wikipedia.org/wiki/SMPTE_time_code
  26  * @see http://www.dropframetimecode.org
  27  */
  28
  29 #include <stdio.h>
  30 #include "common.h"
  31 #include "timecode.h"
  32 #include "timecode_internal.h"
  33 #include "log.h"
  34 #include "error.h"
  35
  36 int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
  37 {
  38     /* only works for multiples of NTSC 29.97 */
  39     int drop_frames = 0;
  40     int d, m, frames_per_10mins;
  41
  42     if (fps && fps % 30 == 0) {
  43         drop_frames = fps / 30 * 2;
  44         frames_per_10mins = fps / 30 * 17982;
  45     } else
  46         return framenum;
  47
  48     d = framenum / frames_per_10mins;
  49     m = framenum % frames_per_10mins;
  50
  51     return framenum + 9U * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));
  52 }
  53
  54 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
  55 {
  56     unsigned fps = tc->fps;
  57     int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
  58     int hh, mm, ss, ff;
  59
  60     framenum += tc->start;
  61     if (drop)
  62         framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
  63     ff = framenum % fps;
  64     ss = framenum / fps      % 60;
  65     mm = framenum / (fps*60LL) % 60;
  66     hh = framenum / (fps*3600LL) % 24;
  67     return av_timecode_get_smpte(tc->rate, drop, hh, mm, ss, ff);
  68 }
  69
  70 uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff)
  71 {
  72     uint32_t tc = 0;
  73
  74     /* For SMPTE 12-M timecodes, frame count is a special case if > 30 FPS.
  75        See SMPTE ST 12-1:2014 Sec 12.1 for more info. */
  76     if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
  77         if (ff % 2 == 1) {
  78             if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
  79                 tc |= (1 << 7);
  80             else
  81                 tc |= (1 << 23);
  82         }
  83         ff /= 2;
  84     }
  85
  86     hh = hh % 24;
  87     mm = av_clip(mm, 0, 59);
  88     ss = av_clip(ss, 0, 59);
  89     ff = ff % 40;
  90
  91     tc |= drop << 30;
  92     tc |= (ff / 10) << 28;
  93     tc |= (ff % 10) << 24;
  94     tc |= (ss / 10) << 20;
  95     tc |= (ss % 10) << 16;
  96     tc |= (mm / 10) << 12;
  97     tc |= (mm % 10) << 8;
  98     tc |= (hh / 10) << 4;
  99     tc |= (hh % 10);
 100
 101     return tc;
 102 }
 103
 104 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum_arg)
 105 {
 106     unsigned fps = tc->fps;
 107     int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
 108     int hh, mm, ss, ff, ff_len, neg = 0;
 109     int64_t framenum = framenum_arg;
 110
 111     framenum += tc->start;
 112     if (drop)
 113         framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
 114     if (framenum < 0) {
 115         framenum = -framenum;
 116         neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
 117     }
 118     ff = framenum % fps;
 119     ss = framenum / fps        % 60;
 120     mm = framenum / (fps*60LL) % 60;
 121     hh = framenum / (fps*3600LL);
 122     if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
 123         hh = hh % 24;
 124     ff_len = fps > 10000 ? 5 : fps > 1000 ? 4 : fps > 100 ? 3 : fps > 10 ? 2 : 1;
 125     snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%0*d",
 126              neg ? "-" : "",
 127              hh, mm, ss, drop ? ';' : ':', ff_len, ff);
 128     return buf;
 129 }
 130
 131 char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
 132 {
 133     unsigned hh, mm, ss, ff, drop;
 134     ff_timecode_set_smpte(&drop, &hh, &mm, &ss, &ff, rate, tcsmpte, prevent_df, skip_field);
 135
 136     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
 137              hh, mm, ss, drop ? ';' : ':', ff);
 138     return buf;
 139
 140 }
 141
 142 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
 143 {
 144     return av_timecode_make_smpte_tc_string2(buf, (AVRational){30, 1}, tcsmpte, prevent_df, 1);
 145 }
 146
 147 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
 148 {
 149     snprintf(buf, AV_TIMECODE_STR_SIZE,
 150              "%02"PRIu32":%02"PRIu32":%02"PRIu32"%c%02"PRIu32,
 151              tc25bit>>19 & 0x1f,              // 5-bit hours
 152              tc25bit>>13 & 0x3f,              // 6-bit minutes
 153              tc25bit>>6  & 0x3f,              // 6-bit seconds
 154              tc25bit     & 1<<24 ? ';' : ':', // 1-bit drop flag
 155              tc25bit     & 0x3f);             // 6-bit frames
 156     return buf;
 157 }
 158
 159 static int check_fps(int fps)
 160 {
 161     int i;
 162     static const int supported_fps[] = {
 163         24, 25, 30, 48, 50, 60, 100, 120, 150,
 164     };
 165
 166     for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
 167         if (fps == supported_fps[i])
 168             return 0;
 169     return -1;
 170 }
 171
 172 static int check_timecode(void *log_ctx, AVTimecode *tc)
 173 {
 174     if ((int)tc->fps <= 0) {
 175         av_log(log_ctx, AV_LOG_ERROR, "Valid timecode frame rate must be specified. Minimum value is 1\n");
 176         return AVERROR(EINVAL);
 177     }
 178     if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps % 30 != 0) {
 179         av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with multiples of 30000/1001 FPS\n");
 180         return AVERROR(EINVAL);
 181     }
 182     if (check_fps(tc->fps) < 0) {
 183         av_log(log_ctx, AV_LOG_WARNING, "Using non-standard frame rate %d/%d\n",
 184                tc->rate.num, tc->rate.den);
 185     }
 186     return 0;
 187 }
 188
 189 static int fps_from_frame_rate(AVRational rate)
 190 {
 191     if (!rate.den || !rate.num)
 192         return -1;
 193     return (rate.num + rate.den/2LL) / rate.den;
 194 }
 195
 196 int av_timecode_check_frame_rate(AVRational rate)
 197 {
 198     return check_fps(fps_from_frame_rate(rate));
 199 }
 200
 201 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
 202 {
 203     memset(tc, 0, sizeof(*tc));
 204     tc->start = frame_start;
 205     tc->flags = flags;
 206     tc->rate  = rate;
 207     tc->fps   = fps_from_frame_rate(rate);
 208     return check_timecode(log_ctx, tc);
 209 }
 210
 211 int av_timecode_init_from_components(AVTimecode *tc, AVRational rate, int flags, int hh, int mm, int ss, int ff, void *log_ctx)
 212 {
 213     int ret;
 214
 215     memset(tc, 0, sizeof(*tc));
 216     tc->flags = flags;
 217     tc->rate  = rate;
 218     tc->fps   = fps_from_frame_rate(rate);
 219
 220     ret = check_timecode(log_ctx, tc);
 221     if (ret < 0)
 222         return ret;
 223
 224     tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
 225     if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
 226         int tmins = 60*hh + mm;
 227         tc->start -= (tc->fps / 30 * 2) * (tmins - tmins/10);
 228     }
 229     return 0;
 230 }
 231
 232 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
 233 {
 234     char c;
 235     int hh, mm, ss, ff, flags;
 236
 237     if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
 238         av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
 239                                       "syntax: hh:mm:ss[:;.]ff\n");
 240         return AVERROR_INVALIDDATA;
 241     }
 242     flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
 243
 244     return av_timecode_init_from_components(tc, rate, flags, hh, mm, ss, ff, log_ctx);
 245 }